Hardy to USDA Zone (5)6 There is confusion regarding this selection and/or its name (i.e., 'Nana'). It might be similar or the same as 'Nana Compacta' or 'Gracilis Nana,' which has dense growth, attains a height of about 30 cm; released by T. Smith, Sussex, England, in 1909 (Krüssmann, 1976).